Do You Have Plans In Metric?

Virtually everything on the internet is by definition “World Wide”. Even though Mechanical Elements is physically located in the USA, we have a world audience, so that is a fair question: Do you have plans in metric?

After all, for most of the world, the metric system rules. It is only in the USA that inches and feet with the old English system are still common. Even the English got smart and do not use the English system any more.?.

Personally, I agree. The metric system is so much easier to use, easier to think about, and it makes more sense. No question here. However, as much as I would like to see things change, this country has a lot of history with it, and a lot of people that stubbornly resist the change. I am not sure why, but that is a different discussion.

DIY Plans In Metric

So, do you make versions of your plans in metric?

Well, I am sorry to say, at this time we do not. It would be wonderful, we absolutely agree, but our experience says that is a lot harder than it first sounds.

At Synthesis, the Engineering Company parent of Mechanical Elements, we serve clients all over the world. We also serve clients that manufacture all over the world, so we do a lot of design in metric. Making plans in metric should be no problem. Right?

Experience shows that materials are not so common or even “standard” around the globe. Different materials and different sizes are available in different areas. For example, we did one design of a specialty trailer for a customer to produce in Thailand. We found suppliers there and got lists of available materials, then we did the design and engineering. The Customer then changed their mind to build in the Philippines instead. Unfortunately, some of the materials in the first design were not available there. So, we had to redesign the trailer based on materials available the Philippines.

So, I will admit, the task to make versions of the plans in metric for each geographical area is daunting. Just the research alone to find out what materials are available in each country. Then, all the designs? Certainly, we can, but does it make economical sense? Check out this article on what goes into making the plans for a little perspective.

Yes, we are sympathetic to the desire for plans in metric. However, we do not have a business case to do it.

Plans In English Dimensions

The first plans at Mechanical Elements were done with English dimensions (inches) because that is the material available where we live in the USA. It is hard to get metric materials here, so the first designs are in inches. As you might expect, the snowball expands from there.

Of course, in selling plans, we must also look at the world markets. There is a lot of work that goes into each set of plans, so being quite honest, there has to be some business sense. Because the plans are currently in English dimensions, they sell most in the USA and Canada. That makes it look like the biggest market.

If we had all our plans available in metric, would sales increase in other places? That is hard to say, but you can vote in the comments below. If there is one trailer size that is most important to you for plans in metric, please let us know. We are not promising, but we are very interested to know if customers want this. And the business side asks: “How many customers want it?”

Converting Plans To Metric

So the biggest question for the moment is how to convert the English version plans to metric? Can you do that?

Yes, customers do it all the time. Honestly, Australia is our 3rd largest market, so there is a lot of calculating going on there. Here are some thoughts about making a good conversion.

Look at the overall size of the project. For a trailer, we are talking about the bed size – width, length – and the tongue length. For a gantry crane, we are talking about the total beam width as well as the height of the legs. Similar for hydraulic presses. Start the conversions based on the final outcome you want.
Have a good look at the article for what is safe to change with the plans. Make sure your size changes will fit within these guidelines.
Look at the specification for each component. If the plans call for a piece of rectangular steel tube that is 4″ x 2″ x 1/8″ thick (101.6 mm x 50.8 mm x 3.2 mm thick), substitute a similar metric beam that is at least as thick. For our example, a metric beam that is 100 x 50 x 3 will probably work, but for safety sake, choose the 4.0 mm thick material instead – especially since the outside dimensions are a little smaller in metric.
Some beams will require a little more thinking. For instance, if you are working on one of our Tiny House trailers, you will need to examine I-Beam Choices based on what is available where you live. Use the conversion factors below to determine the right beam. Ask your supplier to help.
Do the above steps with each aspect of the design. Make your conversions consistent, and write them on the drawings. Feel free to round your overall sizes to round numbers, but make sure you are consistent throughout. This way, you will end up with plans in metric.
Double check everything. Best to convert twice and build once.

Metric Conversions

One thing we did to assist our customers from all around the world – we made the plans using inches only. While the titles of our plans are often in Feet, the details on the drawings and the material lists, etc., are all inch dimensions. That makes them easy to convert to mm by simply multiplying by 25.4. (There are 25.4 mm in each inch.)

For Reference, here are some easy linear conversions:

There are 25.4 mm in each inch. To convert dimensions in the plans to metric, multiply: Inches * 25.4 = mm
There are 12 Inches in a foot. To convert the title dimensions from Feet to Inches: Feet * 12 = Inches
Combining these, 1 Foot = 304.8 mm

For things like Axle Capacity, or Trailer Load Limits. Here are some easy force / weight conversions:

1 lb = 0.453592 kg. So a 3500 lb axle capacity = 1587.5 kg axle capacity.
And, a 6000 lb axle capacity = 2721.5 kg
for reference, a 14,000 lb trailer is effectively = 6350.3 kg

One of the hardest things to convert from English to Plans in Metric is the axles because they are not available in the same increments. Always use an axle capacity which is below the direct conversion number. For instance, if the plans say a 3500 lb axle, please use a 1500 kg axle.

By the way, Google has a great converter. Just type “convert 13.5 inches to mm” and it will bring up the calculator for English inches to mm in metric. Super easy and useful.

Finalizing

Many things do convert easily. For instance, in some of our more complicated trailer plans (like the Deck-Over trailers), some parts are water-jet cut from flat sheet. They include CAD files for CNC cutting which can be changed to metric, then adjusted in size to meet your available country material sizes. Getting everything perfect might take some time, but it can be done.

Now you know the full story about Mechanical Elements plans in metric. I am sorry we do not have everything for everyone here, but we are always working to improve. We are making new trailers with new features and updating older plans with new features constantly it is a big job in a small hobby business, which does not support the work full-time.

Thank you for understanding.

Oh, if there is something specific you want, again, please feel free to leave a comment.

Extras – in Metric

By the way, if you need a quick temporary ruler, some of the images in this post are from PrintableRuler.net They have all sorts of cool PDFs to print – Free. I like that website.

As a second side note, (Thought Starter) with respect to metric. Have you ever wondered why even the metric system still uses 360 degrees for a full circle? Have you ever thought about what it would be like to have degrees in 10’s and 100’s too? (Like other metric measurement divisions?) 100 degrees in a full circle? Then smaller units like Centigrees? Or, maybe 400 degrees in a full circle. What do you think? Post your thoughts below. (Interesting, but what would happen with PI? Sine, Cosine, and other calculations we now use with degrees. Maybe radians is the full answer?) I would love to hear your thoughts.

Good luck with your Conversions for Plans in Metric!

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